Continuation is proposed of a program for study of the hydrolases of mammalian acid mucopolysaccharide catabolism. At present, we are attempting the preparation of oligosaccharides from degradation of heparin, which will serve as test substrates for enzymes acting on the O,N-disulfoglucosaminyl linkages in heparin sulfate. In the course of this work, we are also studying the separation, structures and reactions of the disaccharides preparable chemically from heparin. These reference compounds and information regarding their reactivity will be used in structural studies of larger oligosaccharides. Sulfated monosaccharide reference compounds are being prepared by chemical synthesis. Completed work on substrates for alpha-L-iduronidase and alpha-acetylglucosaminidase is being reported.